Cardiology Research and Practice

Research Article

Two-Photon Laser Scanning Microscopy of the Transverse-Axial Tubule System in Ventricular Cardiomyocytes from Failing and Non-Failing Human Hearts

Table 2

Volume and Surface Area Dimensions of the Transverse-Axial Tubule System. Fractions were calculated individually for all cells before averaging. Regions containing the cell's nucleus or autofluorescent beads within the images were excluded before quantitative analysis.
UnitNon-failingFailing 𝑃
V T A T S / V C e l l ∗ [%]8.67 ± 0.627.93 ± 0.64 𝑃 = . 4 1 7
A T A T S / V C e l l [ 𝜇 m²/ 𝜇 m³]0.403 ± 0.0260.343 ± 0.020 𝑃 = . 0 8 1
A C e l l / A C e l l [ 𝜇 m²/ 𝜇 m³]0.327 ± 0.0330.290 ± 0.028 𝑃 = . 4 0 4
A M e m b / V C e l l [ 𝜇 m²/ 𝜇 m³]0.729 ± 0.0420.632 ± 0.041 𝑃 = . 1 1 1
A T A T S / V T A T S [ 𝜇 m²/ 𝜇 m³]4.682 ± 0.1234.476 ± 0.197 𝑃 = . 3 8 6
A T A T S / A M e m b [%]55.68 ± 2.6354.89 ± 2.12 𝑃 = . 8 1 7
V C e l l Apparent cellular volume, that is, volume
surrounded by the exterior cellular membrane
V T A T S Intracellular volume occupied by the TATS
A T A T S Surface area of the TATS
A C e l l Surface of the exterior cellular membrane
A M e m b Total membrane surface area, that is, A C e l l + A T A T S
∗ i n previous studies 𝑉 T A T S / 𝑉 C e l l ratio is referred to as fractional volume, TATS volume fraction, or t index.